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- ItemNon-optimal and optimal fractional control analysis of measles using real data(Elsevier, 2024-07) Wireko, Fredrick Asenso; Asamoah, Joshua Kiddy K.; Adu, Isaac Kwasi; Ndogum, Sebastian; 0000-0002-7066-246XThis study employs fractional, non-optimal, and optimal control techniques to analyze measles transmission dynamics using real-world data. Thus, we develop a fractional-order compartmental model capturing measles transmission dynamics. We then formulate an optimal control problem to minimize the disease burden while considering constraints such as vaccination resources and intervention costs. The proposed model’s positivity, boundedness, measles reproduction number, and stability are obtained. The sensitivity analysis using the partial rank correlation coefficient is shown for the fractional orders of 0.99 and 0.90. It is noticed that the rate of recruitment into the susceptible population (𝜋), the rate at which individuals in the latent class become asymptomatic (𝛼1), and the transmission rate (𝛽) contribute positively to the spread of the disease, while the rate at which individuals in the asymptomatic class become symptomatic (𝛼2), the vaccination rate for the first measles dose (𝛾1), and the rate at which individuals in the latent class recover from measles (𝛿1) contribute significantly to the reduction of measles in the community. Utilizing numerical simulations and sensitivity analyses, we identify optimal control strategies that balance the trade-offs between intervention efficacy, resource allocation, and societal costs. Our findings provide insights into the effectiveness of fractional optimal control strategies in mitigating measles outbreaks and contribute to developing more robust and adaptive disease control policies in real-world scenarios.
- ItemThe relationship between clustering and networked Turing patterns(Chaos, 2024-07) Luo, Xiaofeng; Sun, Guiquan; He, Runzi; Asamoah, Joshua Kiddy K.; Xue, Yakui; Chang, Lili; 0000-0002-7066-246XNetworked Turing patterns often manifest as groups of nodes distributed on either side of the homogeneous equilibrium, exhibiting high and low density. These pattern formations are significantly influenced by network topological characteristics, such as the average degree. However, the impact of clustering on them remains inadequately understood. Here, we investigate the relationship between clustering and networked Turing patterns using classical prey–predator models. Our findings reveal that when nodes of high and low density are completely distributed on both sides of the homogeneous equilibrium, there is a linear decay in Turing patterns as global clustering coefficients increase, given a fixed node size and average degree; otherwise, this linear decay may not always hold due to the presence of high-density nodes considered as low-density nodes. This discovery provides a qualitative assessment of how clustering coefficients impact the formation of Turing patterns and may contribute to understanding why using refuges in ecosystems could enhance the stability of prey–predator systems. The results link network topological structures with the stability of prey–predator systems, offering new insights into predicting and controlling pattern formations in real-world systems from a network perspective.
- ItemModelling the transmission behavior of measles disease considering contaminated environment through a fractal-fractional Mittag-Leffler kernel(IOP Publishing, 2024-05) Wireko, Fredrick A.; Adu, Isaac K.; Gyamfi, Kwame A.; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246XThis work utilises a fractal-fractional operator to examine the dynamics of transmission of measles disease. The existence and uniqueness of the measles model have been thoroughly examined in the context of the fixed point theorem, specifically utilising the Atangana-Baleanu fractal and fractional operators. The model has been demonstrated to possess both Hyers-Ulam stability and Hyers-Ulam Rassias stability. Furthermore, a qualitative analysis of the model was performed, including examination of key parameters such as the fundamental reproduction number, the measles-free and measles-present equilibria, and assessment of global stability. This research has shown that the transmission of measles disease is affected by natural phenomena, as changes in the fractal-fractional order lead to changes in the disease dynamics. Furthermore, environmental contamination has been shown to play a significant role in the transmission of the measles disease.
- ItemNumerical investigation of forced convective MHD tangent hyperbolic nanofluid flow with heat source/sink across a permeable wedge(AIP Advances, 2024-05) Assiri, Taghreed A.; Bilal, Muhammad; Mahmoud, Emad E.; Ali, Aatif; Asamoah, Joshua Kiddy K.; Adnan; 0000-0002-7066-246XThe combined effect of wedge angle and melting energy transfer on the tangent hyperbolic magnetohydrodynamics nanofluid flow across a permeable wedge is numerically evaluated. Electronic gadgets produce an excessive amount of heat while in operation, so tangent hyperbolic nanofluid (THNF) is frequently used to cool them. THNF has the potential to dissipate heat more efficiently, thereby lowering the possibility of excessive heat and malfunctioning components. The effects of thermal radiation and heat source/sink are also examined on the flow of THNF. The flow has been formulated in the form of PDEs, which are numerically computed through the MATLAB solver BVP4c. The numerical results of BVP4c are relatively compared to the published work for validity purposes. It has been detected that the results are accurate and reliable. Furthermore, from the graphical results, it has been perceived that the rising impact of the Weissenberg number accelerates the velocity and thermal profile. The effect of the power-law index parameter drops the fluid temperature, but enhances the velocity curve. The variation in the wedge angle boosts the shearing stress and energy propagation rate, whereas the increment of Wi declines both the energy transfer rate and skin friction.
- ItemModelling the dynamics of online food delivery services on the spread of food‑borne diseases(Springer, 2024-05) Addai, Emmanuel; Torres, Delfim F. M.; Abdul‑Hamid, Zalia; Mezue, Mary Nwaife; Asamoah, Joshua Kiddy K.; 0000-0002-7066-246XWe propose and analyze a deterministic mathematical model for the transmission of food-borne diseases in a population consisting of humans and flies. We employ the Caputo operator to examine the impact of governmental actions and online food delivery services on the transmission of food-borne diseases. The proposed model investigates important aspects such as positivity, boundedness, disease-free equilibrium, basic reproduction number and sensitivity analysis. The existence and uniqueness of a solution for the initial value problem is established using Banach and Schauder type fixed point theorems. Functional techniques are employed to demonstrate the stability of the proposed model under the Hyers–Ulam condition. For an approximate solution, the iterative fractional order Predictor–Corrector scheme is utilized. The simulation of this scheme is conducted using Matlab as the numeric computing environment, with various fractional order values ranging from 0.75 to 1. Over time, all compartments demonstrate convergence and stability. The numerical simulations highlight the necessity for the government to implement the most effective food safety control interventions. These measures could involve food safety awareness and training campaigns targeting restaurant managers, staff members involved in online food delivery, as well as food delivery personnel.